Tosoh Corporation

Toyo Soda Manufacturing Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Nikkato Corporation

Toshihiko Arakawa

Takaaki Tsukidate

Kiyoshi Kasai

Toshiyuki Mori

Kuniyoshi Ueda

Yasunobu Kawakami

Naomichi Sakai

Kagehisa Hamazaki

Koji Matsui

Michiyuki Aimoto

Toshio Kawanami

Hiroshi Ohnishi

Hiroyuki Matsumura

Michiharu Ogai

Yoshihiro Matsumoto

Michiharu Ogawa

Shinji Nagata

A novel optical fiber connector part is provided which comprises a ferrule having a capillary hole for holding an optical fiber, the ferrule being formed from a zirconia-alumina composite oxide containing yttria at a content ranging from 2 to 4 mol % in zirconia. In the optical fiber connector part, a sleeve for connecting and holding the ferrule may be formed from zirconia and/or a zirconia-alumina composite oxide. A process for producing the optical fiber connector part is provided wherein the granular zirconia-alumina composed of a particulate zirconia-alumina mixture having an average particle diameter of not more than 1 .mu.m is used as raw material. The granular zirconia-alumina preferably contains alumina at a content ranging from 0.1% to 50% by weight. The process comprises spray-drying a slurry containing a particulate zirconia-alumina mixture having an average particle diameter of not more than 1 .mu.m. The ferrule has a stable spherical face at the tip, and will not deform during long-term connection. The granular zirconia-alumina has excellent sintering characteristics.

Optical fiber connector part and process for producing the same

A shot method wherein a shot media based on zirconia composed of a sintered body of partially stabilized zirconia, of which a substantial quantity of the shot media pass through a sieve of normal sizes with apertures of 2.36 mm or less, of which the mean relative density against the theoretical density of zirconia is not less than 95%, of which the mean grain size is not more than 1.0 .mu.m, and which has a mean Vickers hardness of not less than 1,000 kgf/mm.sup.2, is shot to a work surface.

Shot method

A silicon nitride sintered body having a composition of 1.5-3.0 weight % of Y.sub.2 O.sub.3, 0.1-1.0 weight % of Al.sub.2 O.sub.3 and balance substantially Si.sub.3 N.sub.4, a weight ratio of Y.sub.2 O.sub.3 /Al.sub.2 O.sub.3 being 2.5 or more, which has a density of 3.0 g/cm.sup.3 or more and has a structure in which the minor axes of grains are substantially 6 .mu.m or less. This silicon nitride sintered body is produced by preparing a powder mixture containing Y.sub.2 O.sub.3 powder, Al.sub.2 O.sub.3 powder and silicon nitride powder in the above proportions, the silicon nitride powder having an oxygen content of 1.2 weight % or less, a specific surface area of 9-11 m.sup.2 /g and a metal impurity content of 200 ppm or less; and sintering the powder mixture at a temperature of 1900.degree.-2100.degree. C. and a pressure of 5 kg/cm.sup.2 G or more in a nitrogen atmosphere.

Silicon nitride sintered body having excellent high-temperature strength

A silicon nitride sintered body comprised of 1.5 to 3.0% by weight of Y.sub.2 O.sub.3, 0.1 to 1.0% by weight of Al.sub.2 O.sub.3 and 96 to 98.4% by weight of Si.sub.3 N.sub.4 wherein the Y.sub.2 O.sub.3 /Al.sub.2 O.sub.3 weight ratio is at least 2.5, and having a density of at least 3.0 g/cm.sup.3, exhibits a high oxidation resistance and a high strength at a high temperature. This silicon nitride sintered body is prepared by sintering a powdery mixture consisting essentially of 1.5 to 3.0% by weight of Y.sub.2 O.sub.3 powder, 0.1 to 1.0% by weight of Al.sub.2 O.sub.3 powder, and 96 to 98.4% by weight of Si.sub.3 N.sub.4 powder, the Y.sub.2 O.sub.3 /Al.sub.2 O.sub.3 weight ratio being at least 2.5, the oxygen content in the Si.sub.3 N.sub.4 powder being less than 2.0% by weight and the total metallic impurity content in the Si.sub.3 N.sub.4 being less than 200 ppm, at a temperature of 1,850.degree. to 2,000.degree. C. in a non-oxidizing atmosphere.

Silicon nitride sintered body and process for preparation thereof

Disclosed is a process for the preparation of high .alpha.-type silicon nitride powder, wherein a nitrogen-containing silane compound and/or amorphous silicon nitride is crystallized to form crystalline silicon nitride. In this process, crystalline silicon nitride having a particle size not larger than 0.05 .mu.m is incorporated in an amount of at least 0.1% by weight into the nitrogen-containing silane compound and/or amorphous silicon nitride, the mixture is formed into a power or molded body having a powder bulk density of at least 0.1 g/cm.sup.3 as silicon, and the powder or molded body is heated to 1,350.degree. to 1,700.degree. C. while controlling the temperature-elevating rate to at least 15.degree. C./min throughout the temperature range of from 1,200.degree. to 1,350.degree. C. The resulting high .alpha.-type silicon nitride is composed of a fine granular crystal and the does not contain a needle crystal or columnar crystal.

Process for preparation of high .alpha.-type silicon nitride powder

A high .alpha.-type silicon nitride powder is prepared by thermally decomposing a mixture of a crystalline silicon nitride powder having an oxygen content of at least 1.0% by weight and a nitrogen-containing silane compound.

Process for preparation of high-type silicon nitride powder

A silicon nitride powder having an enhanced sintering activity is prepared by heating a mixture of a nitrogen-containing silane compound and a sintering aid in a non-oxidizing atmosphere.

Process for preparation of silicon nitride powder of good sintering

Growing community of inventors

Yokohama, Japan

Toshihiko Arakawa